Three Towers is the seat of House Costayne, a noble house sworn to the Hightowers in The Reach. Their sigil is quartered, with a silver chalice on black and a black rose on gold. The Costaynes are a semi-powerful house and have seemingly never been satisfied with their sworn lords of Oldtown. During both the Blackfyre rebellion and the Dance of Dragons, the Costaynes have both times chosen the opposite side of their overlords. The most famous member of the Costayne family is Long Tom, who served in the King's Guard for sixty years.
- The Three Towers, a castle sits on a cliff, boasting three magnificent towers.
- Main Town, is a quaint area that contains sept and a septry on its own cliff near the Three Towers.
- Fields and Plains, the surrounding lands are covered in beautiful fields and large swept plains, full of southern Reach agriculture.
- Holdfast, to the east of the town lies the only holdfast, but throughout the lands small villages have appeared and sworn themselves to the Costaynes.